Rare-earth elements RE3+ (RE=Sm, Eu, Yb) form impurity centers in fluorite-like crystals MeF2 (Me=Ca, Sr, Ba, Cd). The crystal structure of cubic, trigonal and tetragonal centers in MeF2 has been investigated in the framework of shell model and pair potential approximation. The crystal field parameters were calculated with the exchange charges model, using the optimized geometry of the doped host matrix. With these parameters we have been calculated the optical spectra and spin-Hamiltonian (g-factors) of RE3+ in MeF2, for some combination of R3+ and MeF2. The obtained results were discussed and comparison with experimental data was made. A good agreement confirms the method and model of calculations. © 2010 American Institute of Physics.